We have reported that extracorporeal immunoadsorption to remove circulating immune complexes (CIC) and IgG results in complete regression of feline lymphosarcoma, clearance of persistant feline leukemia virus infection and histologic changes associated with improvement in Kaposi's Sarcoma (KS) in man. We are proposing to investigate the usefulness of an immunoadsorbent in removing CIC and IgG from the plasma of patients with KS and evaluate the clinical responses following this treatment. In addition, we will evaluate the physical proformance of the immunoadsorbent during plasma perfusions. These analyses will enable us in Phase I to determine if there is a modification in the biologic response as a result of extracorporeal protein A immunoadsorption which is associated with clinical improvement and will assist in the development of a safe commercially available treatment device. In order to remove CIC and IgG by extracorporeal immunoadsorption, protein A which binds to the Fc of IgG will be covalently bound to a solid matrix. Columns will be made using the immunoadsorbent. Plasma of patients with KS will be perfused over the columns to remove CIC and IgG and the treated plasma returned to the host. The CIC, IgG and any other molecules bound to the column can then be eluted from the immunoadsorbent for characterization. CIC are associated with several disease states including KS; therefore, if we can demonstrate the removal of CIC from the plasma of KS patients during extracorporeal immunoadsorption then a wide range of treatment modulates may become available to clinicians. Immunoadsorption technology has been demonstrated by us as well as others to have potential therapeutic value in areas such as cancer and immune related diseases where the population base may be as large as 20 million patients or more. Our studies may result in the development of better clinical treatment products for cancer and immune related diseases and also may provide basic information about the immunologic interaction between the host and its tumor.